End-cap device for a syringe (10) having a barrel (11) forming a reservoir (12), and a tip (13) projecting axially from said barrel (11), said end-cap device comprising: a rigid ring (20) engaged on said tip (13)； an inner cap (30) made of a deformable sealing material； and a rigid outer shell (40) fastened around said inner cap (30), suitable for coming into engagement with said ring (20)； said device being configured so that said inner cap (30) comes into leaktight contact with said tip (13) when said outer shell (40) is in engagement with said ring (20), said inner cap (30) being released from said tip (13) when said outer shell (40) is released from said ring (20)； said outer shell (40) forming a sleeve including a bottom axial opening co-operating with said ring (20), and a top axial opening (44), said outer shell (40) including at least one side slot (45) in its peripheral surface, said inner cap (30) including a head portion (35) including a distal axial end edge (37), and a radial shoulder (36), said head portion (35) being fastened in said outer shell (40) by being jammed between a radial bearing surface (46) in abutment against said radial shoulder (36), and at least one radial projection (47, 48) co-operating with said distal axial end edge (37), said radial bearing surface (46) being formed by a proximal axial edge of said at least one side slot (45).注射器的端帽裝置，注射器具有形成貯存器的筒體及從筒體軸向突出的尖端，端帽裝置包含與尖端齧合的剛性環，可變形密封材料製成的內帽，和圍繞內帽緊固並適合與環齧合的剛性外殼，裝置使外殼與環齧合時內帽與尖端無洩漏接觸，外殼從環脫離時內帽從尖端脫離，外殼形成具有與環配合的底軸向開口及頂軸向開口的套筒，外殼在外圍表面包含至少一側槽，內帽包含具有遠軸向端邊緣的頭部及一徑向肩部，頭部透過卡位於緊靠徑向肩部的徑向支撐面和與遠軸向端邊緣配合的至少一徑向突部之間而緊固於外殼中，徑向支撐面由至少一側槽的近軸向邊緣形成。
